Frost dates for 80138Parker, CO
The average last spring frost in Parker is May 9 and the average first fall frost is October 3, giving a typical growing season of about 145 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 9
- Average first fall frost
- Oct 3
- Growing season
- 145 days
Safer after May 23 (1-in-10 risk)
Possible by Sep 21 (1-in-10 risk)
Last frost typically in 194 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 8 · May 20 · Jun 2 | Sep 12 · Sep 25 · Oct 6 | 126 days | 100% |
| Frost / freeze (32°F) | Apr 27 · May 9 · May 23 | Sep 21 · Oct 3 · Oct 15 | 145 days | 100% |
| Hard freeze (28°F) | Apr 15 · Apr 29 · May 12 | Sep 29 · Oct 12 · Oct 23 | 165 days | 100% |
Planting calendar for Parker
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 8 – Jun 14 |
| Tomatoes | Transplant outdoors | May 25 – Jun 13 |
| Peppers | Start seeds indoors | Apr 8 – May 9 |
| Peppers | Transplant outdoors | Jun 8 – Jul 9 |
| Eggplant | Start seeds indoors | Apr 25 – May 24 |
| Eggplant | Transplant outdoors | Jun 8 – Jul 9 |
| Cucumbers | Sow outdoors | Jun 8 – Jun 23 |
| Summer squash | Sow outdoors | May 25 – Jul 9 |
| Winter squash & pumpkins | Sow outdoors | Jun 8 – Jul 9 |
| Snap beans | Sow outdoors | May 25 – Jul 16 |
| Sweet corn | Sow outdoors | May 25 – Jun 13 |
| Watermelon & cantaloupe | Sow outdoors | Jun 8 – Jul 9 |
| Okra | Sow outdoors | Jun 1 – Jun 24 |
| Peas | Sow outdoors (spring) | Apr 8 – May 24 |
| Potatoes | Plant outdoors (spring) | Apr 8 – Jun 8 |
| Onions | Start seeds indoors (spring) | Feb 25 – Mar 24 |
| Onions | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (spring) | Mar 21 – Apr 24 |
| Broccoli | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (fall) | Jun 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 11 – Apr 8 |
| Cabbage | Transplant outdoors (spring) | Apr 8 – May 9 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 8 – Jun 24 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Apr 1 – May 15 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 8 – May 29 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 25 – May 15 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 9 – Jun 24 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 80138 is matched to the NOAA station Parker, CO, 2.5 km away, at 5,904 ft elevation (166 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Parker, CO (used) | 5,904 ft | May 9 | Oct 3 |
| Denver Centennial Ap, CO | 5,883 ft | May 5 | Oct 8 |
| Cherry Creek Dam, CO | 5,647 ft | May 7 | Oct 8 |
| Elizabeth 2Nw, CO | 6,611 ft | May 16 | Oct 2 |
Frost dates near Parker
- Aurora, CO 80016 · last May 9, first Oct 3
- Parker, CO 80134 · last May 9, first Oct 2
- Castle Rock, CO 80108 · last May 9, first Oct 2
- Lone Tree, CO 80124 · last May 5, first Oct 8
- Franktown, CO 80116 · last May 9, first Oct 2
- Englewood, CO 80112 · last May 5, first Oct 8
- Littleton, CO 80130 · last May 5, first Oct 8
- Elizabeth, CO 80107 · last May 16, first Oct 2
Frequently asked questions
- When is the last frost in Parker, CO?
- For ZIP code 80138, the average last spring frost (32°F) is May 9, based on NOAA 1991-2020 climate normals for the Parker, CO weather station. There is a 1-in-10 chance of a frost after May 23.
- When is the first frost in Parker, CO?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 21, so tender plants are at risk from that point on.
- How long is the growing season in 80138?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 145 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.